A new early ripening seedless grape cultivar Tiangong Cuixiangmi

Abstract: Tiangong Cuixiangmi is a new diploid seedless grape cultivar, derived from the cross between the diploid seedless grape cultivar Flame Seedless (♀) and Hanxiangmi ( ), obtained by means of in vitro ovule culture- embryo rescue in Institute of Horticulture, Zhejiang Academy of Agricultural Sciences (ZAAS). In 2013, hybrid embryo rescue breeding was carried out, using Flame Seedless as the female parent and Hanxiangmi as the male parent, and obtained 143 embryo rescue hybrid seedlings. In 2014, we planted them and initially selected them as excellent lines in 2017. Through observation in 2017—2018, we screened out a superior offspring with the number of 13-15-558, which has the characteristics of excellent flower bud differentiation, early maturity, seedlessness, crisp pulp texture, fruitfulness, etc. and finally was named Tiangong Cuixiangmi. The plant has medium growth vigor. The shoot is up- right and the shoot tip is half open with hair. The color of the dorsal side of internodes is green with red strips, while the color of the ventral side of internodes is green. The upper surface of the young leaves is light red and fluffy. Mature leaves are simple, nearly round, and green. The leaf surface has medium bubble-shaped protrusion, serrated and lobed edge on both sides, with 5-lobes, the upper lobes being open, U-shaped, the lower lobes being V-shaped. Petiole depression is open at the base and the petiole is red. There is no villus creeping between the main veins on the lower side the leaf, and leaf vein contains anthocyanins. Flowers are amphoteric and inflorescence born at 2-3 nodes. The compact cluster has an average weight of 372.5 g, with the maximum of 761.0 g. The berry is elliptic shaped, yellow green, with an average weight of 3.2 g. The skin is thin, crispy, with no astringency. The flesh is medium hard, crispy, colorless, juicy and sweet. The average soluble solid content is 20.2%-21.3%. Tiangong Cuixiangmi is an early- ripening variety. Under the greenhouse cultivation conditions in Haining area, Tiangong Cuixiangmi bud breaks in mid- March, flowers in late April and ripens in late June, which is 5- 7 days earlier than Hanxiangmi and the same as Tiangong Moyu. The average rate of budbreak is 82.50%, and the rate of bearing shoots is 86.4%, with well flower bud differentiation, high and stableyield. The vines have vigorous growth with good adaptability to environment and high disease resistance. Orchard should have neutral sandy soil with good moisture and fertilizer retention. The cultivar is suitable for planting under rain shelter cultivation conditions. It is recommended to use a plant spacing of (2.5-3.0) m × (1.5-3.0) m and“flying bird”T shaped dtrellis system. Pinching is recommended leaving one leaf above the inflorescence to enhance the elongation of the inflorescence. The“messenger flower”in the cluster opens, pinching is carried out again removing all the side shoots. The central shoots are mainly pruned in winter, with 4000 canes per 666.7 m2 each with only one cluster left. The fruit clusters are treated with 50 mg · L- 1 GA3 8-10 days after flowering. From budbreak to flowering, measures should be taken to prevents gray mold, top ditch leaf beetle and aphid; before bagging, anthrax should be well controlled; and after harvest, Spodoptera litura and leafhopper should be well controlled.